Apparatus for treating particulate material with gaseous media



March 10; 1959 E. LOWE ETAL 2,875,558

. APPARATUS FOR TREATING PARTICULATE MATERIAL WITH GASEOUS MEDIA FiledJan. 18, 1956 s She ets-Sheet 1 I E.LOWE a E.L.DURKEE I INVENTORS 5%ATTORNEYS.

March 10, 1959 E. LQWE ETAL APPARATUS FOR TREATING PARTICULATE MATERIALWITH GASEIOUS MEDIA Filed Jan. 18, 1956 5 Sheets-Sheet 2 E. LOWE 8| E.L.DURKEE INVENTORS ATTORNEYS March 10, 1959 E. LOWE ETAL APPARATUS FORTREATING PARTICULATE MATERIAL WITH GASEOUS MEDIA Filed Jan. 18, 1956 5Sheets-Sheet 3 52mm... mm Q? E ZEWE: m n v A a R m @E w. w m w o L E w\8 %w z. 5/ h w a F .1 -1 D v m ru m m 5 0% 8 m m m m n. m AS522 mm 8 gom 8 u QJEME m m m m mm L N H. m m I l l a l 8 I D g w I D a L r IINVENTQRS H33 4; l? ATTORNEYS March 10, 1959 E. LOWE ET AL- APPARATUSFOR TREATING PARTICULATE MATERIAL WITH GASEOUS MEDIA Filed Jan. 18, 19565 Sheets-Sheet 4 EXHAUST GAS MATERIAL TO BE TREATED E. LOWE 8| FlG.4

E.L. DURKEE INVENTORS ATTORNEYS Mal-Ch 10, 1959 E. LOWE ETAL 2,876,558

APPARATUS FOR TREATING PARTICULATE MATERIAL WITH GASEOUS MEDIA I FiledJan. 18, 1956 5 SheetsSheet 5 GAS GAS GAS M 9| A gr ss Q Q Q Q Q -Q| Q QQ 0 0 Q 0 s3 s4 85 L f 86 -a7 f 830 a| E.L. DURKEE INVENTQRS BAY a a lia-.1 LmM APPARATUS FOR TREATIN G PARTICULATE MATERIAL WITH GASEOUS -MEDIAEdison Lowe, El; Cerrito,, and Everett L. Durkee, El

Sobrante, Calif assignors to. the United States of. Americaasrepresentedby; the Secretary ofAgrieulture.

Application January 18,1956, Serial No. 560,045

6. Claims. (Cl..34-236) (Granted under. Title $5, U. S. Code (1952),see. 266) A non-exclusive, irrevocable, royalty-free license in theinventionherein. described, throughout. the. world for. allpurposes of.the United... States Government, with the power. to grant sublicenses.for such. purposes, is. hereby granted. to. the Government. of theUnited. States of America.

This application is..a continuation-in-part of our prior, corpendingapplication, for patent Serial. No. 479,688,. filed Jan. 3, 1955, nowabandoned.

This invention relates to. apparatus .for treating partieulate solidmaterials with gaseous media and the gen: eralobject. of the inventionis the provision of .a continuous belt. trough device especially usefulfor treating fruits, orvegetables, such as peas, lima beans, carrots,sliced: cabbage, prunes, apricots, sliced apples, chopped water-.cress;meats; nuts; cereals; and' other solid particulatematerials. Thetreatment effectuatedby the. de: vice may be, for example, dehydration,freezing, blancha ing, cooking, smoking, or combinations of suchtreatments, asisdetermined by the composition and/ or physi-. calcondition of the gaseous medium applied to the ma-, terial undertreatment.

Aparticular object of the invention is the provisionrof apparatus of theabove type wherein the. particulate material. under, treatment is.maintained in the form of a bed, having; a uniform depth and whereinadjustment means visprovided so that the uniform bed. depth can bemaintained, with different materials .and with. different conditions ofoperation. A particular feature of the adjustment means is that the beddepth can be regulated While the device is in operation withoutinterfering with the flow of material, traverse of the belt, treatmentof thematerial, or other operations or functions of the device.

One advantage of the invention is that many different types of materialscan be treated and in every caseeach piece of material is treated to thesame extent. because the material is continuously mixed while maintainedin a bed of uniform depth whereby eachparticle .is-contacted withessentially the same amount of the gaseousmedium.

Another feature is that the material is not crushed nor broken during;treatment because the mixing is gentle yetthorough. The device is thusparticularly adapted'to the treatment of fruit and vegetable materialswhere it isimportant to preserve the size and shape of the pieces. Forexample, in drying apple slices on the present device the edges of theslices are not rounded off as with known drying devices which exertexcessive forces duringmixing.

A further feature is that the device can be operated for longperiods, oftime without. requiring shut-downs for cleaning; because the belt can becleaned during operae tion without-interference with the treatment.process;:this is very important in food processing where sanitaryconditionsmust be. maintained." Further, by operating for; long-periodsof timewithout shutedown, important economic benefits are-gained and theamountof' substandard. product produced. at periods. of shut-down and 2*statt-up,, wheu. thermodynamic. or other treatment con ditions aretransient and not in equilibrium, is reduced to aminimum.

An additional aspect of the inventionis that. the device is flexible in,that it is capable of handling a Widevariety of solid materials and thedegree or type of treatment; can be readily changed. during operation bycontrol of such factors as gas volume and temperature, gas composition,slope and speed of. the belt, and'rate of feed of the material. beingtreated.

Further, objects, features, and advantages of the invention will beapparent fromv the description herein, con-.

sidered. together with. the annexed drawing. drawing:

Fig. 1 is a three-dimensional view of one form of apparatusin accordancewith this inventiornparts being broken away for clarity ofrepresentation.

Fig. 2.is a crossrsection-taken on plane 22 of Fig. 1.

Figs... 3, 4, 5,. and 6 depict another modification of apparatusvwithin. the scope of the invention. Fig. 3 is a-plan view of, thedevice; Fig. 4 isa cross-section taken on plane v44of Fig. 3; Fig.5 isacross-section taken on In the plane 5-5 of Fig.3; Fig. 6 is across-section on a reduced scale taken. on. plane 66 of Fig. 4. In allfour figures, parts are omitted or broken away for clarity ofrepresentation.

Referringwith more particularity to the drawing, in which, like numeralsrepresent like parts, the device of Figs. 1 and 2,.includes aframe 1which carries an endless flexible mesh belt. 2 which is continuouslytraversed in the. directionas shownby the, arrows. The upper bight ofthe belt isformed into atrough the base of which is intheform ofaninclin dv plane as clearly evidentin Fig; 2.v

Material to-betreated is fed into the trough viahopper 3.. This materialis continuously transported along the length of the trough (right toleft in Fig. 1) while being continuously mixed, and. subjected tocontact With a gaseous treatingmedium.v During its, traversal throughthe trough, the material is maintained as a bed 4 having essentiallyuniform depth. Due to the motion of belt 2, thematerial does not remain,quiescent but is sub iect to continuous mixing Thus the materia'ljat thebottomofthe bed and nearestto thebelttends to-ride up the belt in the.direction of; belt travel. When this material reaches. the. upper partof] the trough (above roller 7). it lSyli fid to the top of the bed andslides down the upper surface of the. bed. towardithe, lower part, ofthe trough. Theascending and descending paths of'the rnaterial in the.trough: areshown by arrows 46. in Fig. 2; Thisgentle; but thorough. andcontinuous mixing, action contributesgreatly towardobtaining uniformtreatment. Thematerial in the bed. circulates as described above andalso has aeomponent. of 'motiontowardthe discharge end of the.devicebaused eitherb'yfeedingthe material at suchliate. that the bed 4.is,. sli ghtly deeper in thevicinity of :-feed.,hopper, 3 'thanitis atthe discharge end near hopper 5,.orfby sloping "the device-so thatthefeed end (near hopper .3) is. higher than thedischarge end (near hopper5:). The treated material is thus discharged via hopper 5...

The meansfor supporting and traversing belt Zincludes toothed rollers'6,7, and. 8 journaledon frame 1 These rollers are eachpositively rotatedin the same direction and at the same speedby atsuitable. sourceof powersuch as;a: variable; speed electric motor equippedwith belts and pulleys.c(not illustrated).

The gaseous treating medium is forced intoduct 9-by' ablower or othersuitable-mechanism (not illustrated) and the medium then flows upwardly.athroughaflexible connector:10,' made of: rubberized fabric or. thelike, through the bed of material 4 causing the desired treat- PatentedMar. 10, 1959 bent of the material, for example, dehydration of thematerial where the gaseous, medium is hot, arid air or other suitablegaseous dehydrating medium.

The means for maintaining belt 2 in the form of a trough with a planarbase is described as follows:

The pan, generally designated as 11, is composed of feed-end plate 12,discharge-end plate 13, slotted base plate 14, and side members 15 and16, all of these being joined together to form a unitary structure. Thebase plate 14 is provided wtih slots 20 (Fig. 1) so that the gaseousmedium can pass through this member and eventually through belt 2overlying it. There is a slot 17 between the base plate 14 and sidemember 16 (Fig. 2), whereby to permit the teeth on roller 7 to contactand drive belt 2. Flanges 18 depending from base plate 14 provide themeans to connect flexible connector with this member and so direct thegas stream'through the material lying on belt 2 above plate 14. I

It is evident that since base plate 14 provides a plane surface, theportion of the belt 2 lying thereon assumes a plane surface. Thus thebed of material 4 has a uniform depth in the area where it is subjectedto the flow of gaseous medium from duct 9; hence uniform treatmentoccurs, each piece of material being subjected to contact withessentially the same amount of gaseous medium. For example, where thedevice is used as a dehydrator and the gaseous medium is hot air orother suitable gaseous dehydrating a'gent, each particle of material isdehydrated to the same extent, because each particle is contacted withessentially the same volume of hot air.

It is also to be noted that the arrangement of the belt drive rollers isparticularly adapted to cause the belt to assume a plane surface duringits traverse over base plate 14. Thus each of the rollers 6, 7, and 8 ispositively driven in the same direction and at the same speed. Thismeans that the belt will not tend to pull away from base plate 14 as'itmight if for example roller 6 were not positively driven. It is also benoted that the top surface of roller 7 is essentially in the same planeas the top surface of base plate 14; this means that the belt 2 does nottend to be lifted but maintains its position lying on the floor of plate14.

As mentioned briefly above, one of the features of the present inventionis that the slope of plate 14 (and hence the slope of bed 4) can beadjusted easily. The importance of this feature is that thereby a bed ofmaterial of uniform depth can be maintained with any type of material.Thus the device can be adjusted so as to correlate it with the speed ofthe belt and with the angle assumed by the bed of circulating materialso that regardelss of the type of material used the material will notpile up at the low or the high endof the trough but will maintain auniform depth throughout. To illustrate this pointwith a constant beltspeed of 3 ftQ/min. in drying sliced apples, plate 14 is maintained atapproximately 30 from the horizontal to keep the apple slices ,in a bedof uniform depth. Under the same conditions but for drying peas, theplate 14 is maintained at approximately 20 to maintain uniform bed depthwith this commodity. The angle assumed by the bed of circulatingmaterial is somewhat analogous to the angle of repose of a mass ofstatic material. In the latter case the criterion of the angle is thenature of the material (particle size, shape of particles, etc.) whereasin the former case the angle depends not only on the nature of thematerial but also on the speed of the belt which supports the bed and tosome degree on the surface characteristics of the belt. In general theangle assumed by the bed of circulating material is steeper than theangle of repose of the same material. t

The means for accomplishing the slope adjustment is explained asfollows: v

End plates 12 and 13 are. drilled soithat shaft-19 which is..splined to.roller ;7 passes freely. throughftheseiplates; By this means the entirepan 11 can be rotated about the slack so that the bottom plate 14.

axis'of shaft 19' to tilt the base plate 14 to different angles. Tocontrol the degree of tilt there are provided brackets 25 and 26attached to end plates 12 and 13, respectively. These brackets bearthreaded rods 27, 28, nuts 29, 30, and plates 31, 32, the last restingon horizontal member 33 of frame 1. By rotation of nuts 28 and 29 thebase plate 14 and, hence. the plane surface of belt 2 resting on it canbe adjusted to any desired degree of slope. Belt 2 is arranged with aslack portion at 2' whereby to allow the distance between roller 6 andthe base plate 14 to be varied when a change in tilt is made. If theamount of slack is not suflicient, as for example, where base plate 14is tilted to a large angle from the horizontal, the power'may be turnedofi for a moment or two to stop belt 2 and then the belt maybe manuallyre-positioned on roller 6 to provide enough of the belt will lie flat onbase It is particularly to benoted that since base plate 14 andconnected parts are hinged on shaft 19 which also bears roller 7,changing the slope of plate 14 will not atfeet engagement of belt 2with'roller 7. Thus no matter what angle of slope is used, belt 2 willride properly on roller 7 and no adjustment at this point is needed.Likewise, no matter how the slope of plate 14 is changed, the belt 2will still lie on the floor of this plate.

' In order to continuously clean belt 2 there is provided pan 40 filledwith hot water or other cleansing liquid. Belt 2 continuously travelsthrough the water in its course from roller 8 to roller 6. Air is forcedby pipe 41 into slotted conduit 42 the air being blown out of slot 43against belt 2 drying it and blowing away particles of debris, etc. Ifdesired, the pan of water and air blast may be supplemented by steamjets, rotating brushes, sprays of water or the like.

Usually, the trough portion of belt 2 from one edge to the other ismaintained level, that is, the edge of the belt at the feed end (nearplate 12) and the edge of the belt at the discharge end (near plate 13)are at the same elevation. The passage of the material from the feed endto the discharge end is caused by feeding the material at such a ratethat the bed of material is slightly higher'at the feed end than at thedischarge end. However, if desired the trough may be sloped so that thedischarge end is somewhat lower than the feed end by providing the legsof the device with adjustable feet. 1

As shown in the drawing, the material being treated is subjected to ablast of gas from a single source. If desired duct 9 and connector 10may be compartmentized so that as the material progresses from feed endto discharge end, it is subjected to gas at different temperaturesand'lor volumes. Mechanism for accomplishing such a result is disclosedbelow in connection with the modification of Figs. 3 to 6. v To regulatethe depth of material in bed fhopper S is vertically adjustable inguides 44. Plate 45whi'ch is integral with hopper 5 thus acts asa wierto control the depth of bed 4. The entire device may, if desired, besurrounded with a housing having suitable inlets for material to betreated and treating gas and outlets for treated material and exhaustgas. The advantage of a housing is that the ex haust gas may then becarried by a suitable duct out of the building or used for otherpurposes' Also, where a housing is used, the exhaust gas may berecirculated into the device after suitable regeneration treatment. Forexample, where the device is-used'as 'a free zer, the ex"- haust gas maybe re-cooled and then "circulated'back to duct 9 for freezing of theparticles'in'the bed. I

As notedhereinabove, the device of this invention is of a versatilenature and may be. employed to efiectuate diverse types ofoperationswhich involve-contacting pat ticulate solid material with agaseous, agent.- -Alsoas noted .above,;by providing meansformai'ntaining .the particulate material in the form of a bed havinguniform depth,

each particle is subjected to the same degree of treatment. One aspectoftheinvention concerns. the meet the-device as a' dehydrator forevaporating moisture from particulate material especially fruits,vegetables, meats, nuts, cereal grains, and so'forth. Indehydration'appli cations, the gaseous agentforcedlupwardly through-bed 4"is usuallyhot air or other hot gas suitablefor dehydrating purposes.

Another application of the device is its use-as-afreezer. In-this case,the gaseousmedium is air, carbon dioxide, trichloromonofluoromethane,trichlorotrifiuoroethane, etc., in-a refrigerated state; By thecontinuous-mixing of the material in the bed during contact of therefrigerated gas and material, the particles are rapidlyand'uniformlyfrozen without sticking together, that is, theproduct is a freeflowingmass of individual frozenparticlesessentially free from aggregates ofindividual particles:

A further aspect of the invention concerns the-use of the device as acooker or blancher; In-such case; the gaseous agent is steam, mixturesofsteam and hot air, or other hot, preferably humid, gas or vapor;

An additional aspect of the inventionconcernsthe use of the devicetotreatparticulate materials with various chemical agents. For example,in the processing of fruits and vegetables it isoften-desiredtoimpregnate the food particles with agents whichinhibitenzyme activity; agents which inhibit browning; agents whichinhibit rancidification of fat components in: the food; flavoringagents; preservative agents; and so forth. Insuch applications, theagent in question is incorporated'into 'thesgas stream entering via duct9. Examplesof agents which maybe so employed are: sulphurdioxide toinhibit browning of the food particles; butylated.hydroxyanisole, propylgal! late, or other volatile organicfat-stabilizing antioxidant tominimize rancidificationof fat constituentsin the food particles; woodsmoke,.pyroligenous acid,:acetic acid,-.etc. to act as flavoring andpreserving agents; lemonoil, orange oil, cinnamon oil, or: othervolatileessentialoilsor-fruit essences in order to; impart-desiredflavors to the food particles.

In any of the diverse applications of the device ofithis invention, thegaseous medium-which contactsthe particles iii-bed 4 need notnecessarilybeeentirely'iri;the gaseous state. Thus the medium mayconsist: of amajo-r proportion of a gaseous substance havingsuspended-inrit :a minor proportion of minutedroplets ofliquid materialsuch. as water; refrigerant (liquid: trichloromonoc-hloromethane, liquidtrifluorotrichloroethane, etc-.); sulphurous:,acid solution; aceticacid; organic.-antioxidant flavoring substance; 'andiso forth.

It is obvious that by' providing suitable sources of different gaseousmedia and valvearrangements between these sources and=-duct-9, theparticulate material may'be subjected to a series of, distinctoperations; by changing the character of the gas. stream-as; the;treatmentprogresses. As an example of.v such op eratiom-raw dicedcarrots are placed in the device and belt Z is'traversedtto continuouslymaintain the diced carrots; as a bed5-4 ofuniformdepth. The carrots arethensuccessively'subjected to; (a), air containing sulphur dioxide or;steamto inactivate the-enzymes in the carrots; (b) hot airtodehydratethe carrots to the extent that their weight is halvedby evaporation ofmoisture; and (-c) cold air at-about minus 20 F. to rapidly freeze thepartially dehydrated-carrots. During these operations, the diced carrotsare continuously maintained as a bed of uniforrndepthi anddischargehopper 5: is so adjusted that the carrots. are: kept in the bed. Afterthe freezing is completed, hopper 5 is lowered and the dehydrofrozencarrotsare discharged. andpackaged. Other; applications of thedevicefor. conducting sequential operations with. different gaseousmediawill be obvious from the above description.

Reference is now made to. Figs. 3,4, 5, and 6which depicta secondmodificationuof apparatuswithin the ambit of the invention. 'l'htapparatus-cf these f figures can be employed for effectuating any of theaforementioned types of. gas-treatment: as applied-to particulatesolidume terial;

The construction and. operation of the device ofFigs. 3, 4, 5, and 6 isexplained-as follows-:-

The device includes ahousing 6i) providedwith windows 61. Within thehousing is a belt supporting and operating structure generallydesignated as 62, this structure being suspended from the top of'housing60 by rods-63, 64, and 65; adjustable in length.

Structure 62 carries an endless, flexible-mesl1"=b'elt 66 whichiscontinuously traversed in the direction as shown by the arrows in Fig.4: The upper bight' of'the belt-is formed into a trough the base of'which is in the form of an inclinedplane as clearly evidentin Fig. 4;

Material to be treatedis fed'into the system'viachute 67. This materialis continuously transported along the length of the trough (left toright in Fi'g.-3 whilebein'g continuously mixed and subjected to contactwith'a gaseous treating medium. During its traversal through the trough,the material is maintained as abed having an essentially uniformdepthexactly as described above in connection with the modification ofFigs. 1' and2. The circulatory motion of the material in the bed and"the motion of the material from the feed end of the device toward thedischarge end' of the device are also as described in connection-Withthe first modification;

The means for supporting and traversing-belt 66 includes sprockets 68,69, and 70'mounted on shafts 71, 72, and 73, respectively. The drive forthese'sprockets includes the following: On feed-end plate 88 is mounteda shelf 74 on which is located electric motor 755 This motor rotatesshafts 71, 72; 73 and in the same direction and at thesame speed'by' aseries of sprockets 76 and chains 77. Motor '75"is-preferablyofthevariable speed type so that the speed of the belt can be varied asdesired.

The gaseous'treating medium isforcedinto conduit 78 by ablower or othersuitable mechanism (not-illustrated) and the medium flows throughfiexibleconnector 79 into the duct generally designated as 80 which iscarriedhy plates 88 and 89. Duct 80 (see'Fig. 6) is divided into aseries of compartmentsby membersSl and 82 so that there is formed threeindividual 'cornpartm'ents '83, 84, and through which'the gaseousmediumfiows. Vertical partitions 86 and 87 are joined with the members81 and 82', respectively; to discharge the three separate gas streamsof'compartments 83; 84, and 85 upwardly through three separate areas of thebed of material retained in the trough portion of be1t'66'. Bycompartmentizing the gas ductin this way'a more uniform-distribution ofgas to thedifferent areas of the bed is attained. Also sucharrangement'permits more flexibility in that by' providing-the separateducts with valve ar rangements, (83a, 84a, 85a), different areas of thebed may be subjected to, diiferentarnountsof gas or'even differentgases.- Gas which passes through thebed of material is discharged fromthe housing- -by vent'100.

The ,meansfor maintaining belt 66 in the form of a trough with a planarbase is described in more detail as follows:

The structure-62 includes feed-end plate 88 and'discharge-end plate 89,these being joined together into 'a unitary structure by'channels 90.Supported on channels 90 is a grid formed of a series of spaced bars 91'joined to rods 92. The entire grid structure may be lifted off channels9t) for cleaning purposes. The upper'bight of belt 66. rides on topoft-bars 91 and so assumes-the form ofa" trough with a planar base. Thespacing of bars 91 permits free flow of the gas past the bars andthrough the belt into the'bed of material. Also supportedon plates88 and89 are shafts 71, 72, 73 which constitute part of the means fortraversingbelt '66 as' previously described;

Material which has-been treatedas described is cog.

'tinuously discharged through orifice93 in plate 89 (Fig. slides downchute 94 attached to plate 89, and from there is discharged by dischargehopper 95 which is mounted in housing 60 (Fig. 3).

As mentioned hereinabove, one of the features of the invention is thatthe slope of the planar base of the trough of belt 66 can be adjustedeasily and without interference with the operation of the device. Inthis modification, such adjustment is made by altering the length ofrods 63, 64, and 65. Usually, rod 65 is kept at its original lengthsince it is in the center of the trough and its connection with plate 89serves as a pivot about which the trough can be rotated by suitableadjustment of the length of rods 63 and 64. In this way, the speed ofthe belt can be correlated with the type of material being processed sothat the material maintains a bed of uniform depth in the trough portionof the belt. A feature of this modification of the invention is that theadjustment in slope can be made without affecting the position of thebelt 66 on the sprockets 68, 69, 70. Thus in this device, by adjustingthe length of rods 63, 64, 65, the position of structure 62 as a wholeis altered, there is no relative movement caused between the belt andits position on bars 91. Thus adjustment of the slope does not in anyway affect the drive of the belt nor the relation of the belt to the bedof material. For altering the slope of structure 62 in the directionfrom discharge end to feed end, similar adjustment of rods may be made.For example, to increase the slope from discharge end to feed end, rods63 and 64 may be shortened each of the same degree while rod 65 is leftin its original position.

,In order to continuously clean belt 66 there is provided pan 96 filledwith hot water or other cleansing liquid. The belt continuously travelsthrough the water in its course beneath structure62. A series of nozzles97 are provided for forcing steam, hot water, compressed air, etc.against the belt to further clean it. Also provided is a burner 98 whichdirects gas flames against the belt to dry it after cleaning. Adjacentthe upper end of the trough portion of the belt is a roller brush 99.This brush is rotated by motor 75 in the direction shown and serves toreturn to the bed particles of material which cling in the intersticesof the belt.

Having thus described the invention, what is claimed is: e

1. An apparatus having an exterior portion and an interior portion fortreating particulate material in the interior of said apparatus withgaseous media comprising .a ductfor introducing a gaseous medium intothe interior of said apparatus, said duct being provided with .anopening across the top thereof; a planar, perforated, sloping base plateoverlying said opening, the perforations in said base plate beingsmaller than said opening; an

endless foraminous belt; means for continuously traversing said belt;means for maintaining part of said belt in the form of a trough having aplanar base resting upon said base plate, the trough part of the beltbeing adapted to support a bed of particulate material; means forforcing a gaseous medium into said duct and through said opening,perforations, belt, and the bed of material supported thereon; and meansfor adjusting the slope of said base .plate whereby to maintain thematerial in the trough in the form of a bed having an essentiallyuniform depth.

2. An apparatus having an exterior portion and an interior portion fortreating particulate material in the interior of said apparatus withgaseous media comprising a duct for introducing a gaseous medium intothe interior 'of said apparatus, said duct being provided with anopening acrossthe top thereof; a planar, perforated, sloping will changethe position of the belt with relation to said base plate.

base plate overlying said opening, the perforations in said base platebeing smaller than said opening; an end- :lessforaminous belt; means formaintining part of said belt in the form of a trough having a planarbase resting, upon said base plate, the .trough part of the belt a bedat particulate manner-i l eing adapted to support means for forcing agaseous-medium intosaid duct and through said opening, perforations,belt, and the bed. of material supported thereon; means for continuouslytraversing said belt including a positively-driven, rotatable toothedroller adjacent said base plate for driving said belt, the upperperiphery of said roller being substantially tangent to said base platewhereby change in slope of said plate will not interfere with thedriving of the belt by the roller; and means for adjusting the slope ofsaid base plate whereby to maintain the material in the trough in theform of a bed having an essentially uniform depth.

'3. An apparatus having an exterior portion and an interior portion fortreating particulate material in the interior of said apparatus withgaseous media comprising a duct for introducing a gaseous medium intothe interior of said apparatus, said duct being provided with an openingacross the top thereof; a planar, perforated, sloping base plate havingan upper end and a lower end, said base plate overlying said opening,the perforations in the base plate being smaller than said opening, thebase plate being pivotable about an essentially horizontal axis adjacentthe upper end thereof; an endless foraminous belt; means for maintainingpart of the belt in the form of a trough having a planar base restingupon said base plate, the trough part of the belt being adapted to support a bed of material undergoing treatment; means for forcing a gaseousmedium into the duct and through said opening, perforations, belt, andmaterial supported thereon; means for adjustably pivoting said baseplate to change the slope thereof whereby to maintain the material inthe trough in the form of a bed having an essentially uniform depth; andmeans for continuously traversing said belt including apositively-driven toothed roller adjacent the upper end of said baseplate, the upper peripheryof said roller being substantially tangent tosaid base plate whereby change in the slope thereof will not inter,-fere with the driving of the belt by said roller nor will change theposition of the belt with relation to the base plate.

4". An apparatus having an exterior portion and an interior portion fortreating particulate material in the interiorof said apparatus withgaseous media comprising a duct for introducing a gaseous medium intothe interior of said apparatus, said duct being provided with an openingacross the top thereof; a planar, perforated,

sloping base plate having an upper end and a lower end, said base plateoverlying said opening, the perforations in said base plate beingsmaller than said opening, an essentially horizontal shaft adjacent theupper end of the base plate, the base plate being supported by andpivotable about said shaft; an endless foraminous belt;

means for maintaining part of the belt in the form of a trough having aplanar base resting upon said base plate, the trough part of the beltbeing adapted to support a bed of particulate material, means forforcing a gaseous medium into saidduct and through said opening,perforations, belt, and material supported thereon; means tinuouslytraversing said belt in the general direction from said lower end of thebase plate to the upper end thereof, said means including apositively-driven, rotat- ;able'toothed roller on said shaft, the upperperiphery ,of said rollerbjein'g substantially tangent to said baseplate whereby change in the slope thereof will not interfere with thedriving of the belt by said roller nor 5. An apparatus having anexterior portion and an interior portion f0r. t reating particulatematerial in the interior of said apparatus with'gaseous media fortreating particulate solid material with a gas comprising; an assemblyfor maintaining and treating the material" in the form of a sloping bedhaving an essentially uniform depth, said assembly including a duct forintroducing a gaseous medium into the interior of said apparatus, saidduct being provided with an opening across the top thereof; a planar,perforated, sloping base plate overlying said opening, the perforationsin said base plate being smaller than said opening; an endlessforaminous belt, means for maintaining part of said belt in the form ofa trough having a planar base resting upon said base plate, the troughpart of the belt being adapted to support a bed of particulate material;means for traversing said belt along said base plate in the generaldirection from bottom to top of the slope thereof, said means includinga positively-driven sprocket which engages the belt; means for adjustingthe slope of said assembly as a unit without disturbing the position ofthe belt with relation to the sprocket and base plate; and means forforcing a gaseous medium into said duct and through said opening,perforations, belt, and material supported thereon.

6. An apparatus having an exterior portion and an interior portion fortreating particulate material in the interior of said apparatus withgaseous media for treating particulate solid material with a gascomprising: a unitary assembly for maintaining and treating the materialin the form of a sloping bed having an essentially uniform depth, saidassembly including a duct for introducing a gaseous medium into theinterior of said apparatus, said duct being provided with an openingacross the top thereof; a planar, perforated, sloping base plateoverlying said opening, the perforations in said base plate beingsmaller than said opening; an endless foraminous belt; means formaintaining part of said belt in the form of a trough having a planarbase resting upon said base plate, the trough part of the belt beingadapted to support a bed of particulate material; means for traversingsaid belt along said base plate in the general direction from bottom totop of the slope thereof, said means in cluding a positively-drivensprocket which engages the belt; a supporting member for supporting saidassembly, said assembly being suspended as a unit from said supportingmember by a plurality of hangers adjustable in length whereby the slopeof the assembly may be adjusted as a unit and without disturbing theposition of the belt with relation to the sprocket and the base plate;and means for forcing a gaseous medium into said duct and through saidopening, belt, and the bed of material supported thereon.

References Cited in the file of this patent UNITED STATES PATENTS2,308,420 Hoopes Jan. 12, 1943 2,424,228 Erisman July 22, 1947 2,745,194Lowe et al. May 15, 1956 FOREIGN PATENTS 95,687 Sweden May 7, 1939566,662 Great Britain Ian. 9, 1945

